The general aims of the proposed research are to further elucidate the basic interrelationships which exist amongst the CNS, the adenohypophysis, the ovary and adrenal and the sex steroid feedback mechanisms and sites of action. To this specific aims of the program are: 1. To further analyse the neuroanatomic organization of the hypothalamus in its regulation of FSH, LH and prolactin. 2. The quantitative changes induced in Gn-RH and biogenic amines after expprimental manipulation of the preoptic area or other brain regions. 3. The response of the pituitary in in vitro flask and superfusion systems to Gn-RH, cAMP to compare responses to those obtained in vivo. 4. The importance of timing of endogenous estrogen and progesterone secretion to the ovulatory discharge of GTH and the contributions of adrenal steroid secretions to this phenomena. 5. To further elucidate theregulatory processes involved in the pulsatile release of LH in castrate rats. 6. To evaluate further the causes of androgen vs. estrogen-induced sterility after neonatal exposure in rats.